Distinct morphology and self-assembly behavior of Xylan nanoparticles are correlated with arabinose side-chains in Sorghum.

Arabinoxylans (AXs) are complex polysaccharides with varying arabinose substitution patterns that affect their structural properties and self-assembly behaviors. In this study, we selected two sorghum varieties (S2 and S13) from a pool of 18 representative varieties, based on their distinct hemicellulose compositions. Techniques such as arabinoxylan-directed monoclonal antibodies (mAbs), High-Performance Anion-Exchange Chromatography (HPAEC), and 2-D HSQC NMR showed that S13 hemicellulose was of higher Ara/Xyl ratio of 0.22, compared to 0.09 in S2, which should be accounting for relatively high and low branching degrees of xylans. To gain deeper insights into the influence of arabinose side chains on xylan macromolecules, we measured and compared the morphology and self-assembly behaviors of nanoparticles from both varieties. Our findings indicate that nanoparticles from S2 were more slender and tended to assemble in a parallel orientation, while those from S13 displayed a vertical or disordered arrangement. By employing confined evaporation-induced self-assembly (C-EISA), we explored the self-assembly behavior of nanoparticles from each variety, and S13 nanoparticles in particular exhibited greater branching and distinct helical structures. These findings thus extend our understanding of the relationship between hemicellulose structure and its functional applications, offering insight for developing novel materials for drug delivery, biosensors, and other emerging applications.